So sorry you didn't have a wonderful evening. Just maybe she didn't understand what MS was and was too embarrassed to ask you what it was and than felt too awkward to keep up conversation.
Today is a new day and you don't even have to have her over for dinner if you don't want to.
Just a side note, I'm 34 and my DH is 58, we have been married 11 years (but we do have 7 kids so I have enough things to do in the day, LOL).